OK well this was about depression glass, which is not crazy expensive, so my statement that people should pay the cost of replacement was based on that. If it was really expensive, then yes it should be insured. I don't know what the division is between those two categories though.
Some Depression Glass is expensive. It depends on the pattern. I have a DG child's tea set that's worth several hundred dollars. Conversely, I have DG that can be found at a flea market for only a few dollars.
General comment: insuring items. Yes, insuring very valuable items is smart. However, to make a claim based on an item that costs a few hundred dollars makes your insurance rates go up. Having a low deductible has the same affect.
This. And, in some cases, it's not just the price of the item, it is its availability. Some DG pieces are all but nigh impossible to find; I have been delighted to have found several hard-to-get pieces randomly at flea markets and such, but they are few and far between for various items in certain patterns. (Mine s Amber Madrid, one of the more "common patterns/colors, but still with some very rare pieces.) Not only that, but at least in my case, there is a huge sentimental value attached, as it was handed down to my grandmother from her mother, and then on to me. So, I take very good care of it & would be crushed if a piece were to be broken.
As far as replacing broken items, when I have done so, the offer has always been genuine. (In truth, I can't recall breaking anything, but a couple things I have borrowed over the years have gotten lost and I have always replaced them. Broken, lost, same difference.)
For the reverse situation, a lot would depend on the item, the person who broke it, and the circumstances. If it is somebody goofing around & being careless, and it's a valuable item, I would want it to be replaced. However, for most things, I tell the breaker not to give it another thought. My mom comes to visit us between TG & Christmas every year, and every year, she drops something on my tile floor and breaks it; it has become a family meme and we all await anxiously to see what Grandma will break this year.

However, she has been so kind and wonderful and generous throughout the years that I would never ask her to replace anything. And, she knows me well enough to know that I don't place great stock in "things". It was kind of funny, though, when one year she broke the lid of a sugar bowl of a set of SB/creamer/salt shaker/pepper shaker that had been rather expensive and that I really liked as far as my decor. She ran to the Dollar Store and got me a plain glass sugar bowl that is fully functional, and I was perfectly happy with it, just cause that's how I tend to roll.
In the OP, the breaker should have offered the replacement cost of the DG vase.